The present invention relates to a motor-driven pump unit, in particular for antilock systems of motor vehicles.
A motor-driven pump unit of this type already is disclosed in EP 645 875 B1. It comprises an electric motor arranged on one side of a pump unit and an electronic unit arranged on another side of the pump unit. A commutator is mounted at the shaft end of the electric motor that faces away from the pump, and this commutator is acted upon by radially arranged carbon brushes. A supply line that runs through the motor and pump housing up to the electronic unit supplies power to these carbon brushes. The motor-driven pump unit can be improved, because measures have to be taken that the carbon brushes and the brush holding plate can be lowered radially to the commutator after mounting the rotor and the motor housing. For this reason, special tubular brush-holders for the carbon brushes have been proposed, with which the brushes would be held in a retracted position and could be pushed radially out of the tubular brush-holder in the direction of the commutator after a releasing device is activated. However, the tubular brush-holders are no longer accessible after the brush holding plate and motor housing have been mounted, and this is an added problem.
Another disadvantage is that the overall length of the unit increases in relation to the width of the commutator. Little mounting space and particularly a short overall length count among the basic requirements for a unit for motor vehicles. Hence, the object of the present invention is to propose a motor-driven pump unit that can be assembled easily is very small in its assembled state. Furthermore, the contacting between the electrical components is to be simplified.
This object is solved by the present invention by providing means for an axially movable holding device and for the electric contacting of carbon brushes in connection with an axial installation of the unit. Due to the axially movable arrangement of the carbon brushes, it is not necessary to hold back the carbon brushes during certain installation steps on the one hand, and on the other hand the overall length of the entire unit is essentially rendered independent of the width of the commutator because, according to the invention, an axially effective commutator can be used. And, finally, the motor according to the invention does not require a brush holding plate.